The prism: Surface area and volume

The prism is a polyhedron composed by two bases that can be any polygons joined by parallelograms. In a certain way, we can say that, to create a prism, it is necessary to accumulate many equal polygons.

The regular prisms take regular polygons as bases. For example, the following figure is a prism with pentagons for bases:


Calculate the area and volume of a prism of a height of $$10 \ m$$ and with an equilateral triangle as side $$5 \ m$$ for bases.

The area of the triangle is: $$$A= \dfrac{5 \cdot 4,33 }{2}$$$

The side area has a value of: $$$3 \cdot 5 \cdot 10=150$$$

So, the area of the polygon is: $$$A_{prism}=2\cdot 10,82 + 150 = 171,65$$$

And the volume $$$V=10 \cdot 10,82=108,3$$$

Generalizing,$$$A_{lateral}= perimetre_{basis} \cdot height \\Area= 2 \ Area_{basis} +Area_{laterals} \\ Volume=Area_{ basis} \cdot height$$$